KMQ viewer are glasses for viewing a stereoscopic over/under format.
KMQ stands for the inventors' initials: Koschnitzke, Mehnert, Quick.
[1] A recent usage of this technique is the openKMQ project.
Stereoscopic viewing is achieved at a matching distance to the glasses.
Bigger over/under stereo image pairs on either paper or a monitor can be viewed from a proportional greater distance.